The element selenium’s photoelectric properties were discovered accidentally by a researcher attempting to improve the electrical conductivity of undersea cables. Englishman Willoughby Smith worked for the Gutta Percha Company—named for the natural rubbery substance used to coat cables—and oversaw cable laying across oceans from the Mediterranean to the North Atlantic. Shortly after working on the first cable connection from Java to Darwin, Australia, Smith moved from management to his first love, technical engineering problems. Testing selenium showed it to have erratic properties, unsuitable for his needs. But Smith’s curiosity led to a critical discovery in 1873.
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Not one to simply cast the selenium aside, Willoughby Smith investigated further – and discovered that the metal’s electrical resistance was proportional to the strength of light falling on a selenium bar.
Selenium is usually a byproduct of copper refining. Consequently, Belgium, with major refining facilities, is the primary source of selenium imports to the U.S., and imports accounted for a third or more of our consumption in the late 1990s (recent figures are not available because there is only one domestic producer, and the data are withheld to avoid disclosing proprietary company information).
Selenium decolorizes glass, gives ruby-red color to plastics, coats photocopier drums, works in electric-eye doors, is a livestock feed supplement, and helps solar cells and anti-dandruff shampoos do their jobs.